gdb/python/py-block.c

   1 /* Python interface to blocks.
   2
   3    Copyright (C) 2008-2015 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "block.h"
  22 #include "dictionary.h"
  23 #include "symtab.h"
  24 #include "python-internal.h"
  25 #include "objfiles.h"
  26 #include "symtab.h"
  27
  28 typedef struct blpy_block_object {
  29   PyObject_HEAD
  30   /* The GDB block structure that represents a frame's code block.  */
  31   const struct block *block;
  32   /* The backing object file.  There is no direct relationship in GDB
  33      between a block and an object file.  When a block is created also
  34      store a pointer to the object file for later use.  */
  35   struct objfile *objfile;
  36   /* Keep track of all blocks with a doubly-linked list.  Needed for
  37      block invalidation if the source object file has been freed.  */
  38   struct blpy_block_object *prev;
  39   struct blpy_block_object *next;
  40 } block_object;
  41
  42 typedef struct {
  43   PyObject_HEAD
  44   /* The block.  */
  45   const struct block *block;
  46   /* The iterator for that block.  */
  47   struct block_iterator iter;
  48   /* Has the iterator been initialized flag.  */
  49   int initialized_p;
  50   /* Pointer back to the original source block object.  Needed to
  51      check if the block is still valid, and has not been invalidated
  52      when an object file has been freed.  */
  53   struct blpy_block_object *source;
  54 } block_syms_iterator_object;
  55
  56 /* Require a valid block.  All access to block_object->block should be
  57    gated by this call.  */
  58 #define BLPY_REQUIRE_VALID(block_obj, block)            \
  59   do {                                                  \
  60     block = block_object_to_block (block_obj);          \
  61     if (block == NULL)                                  \
  62       {                                                 \
  63         PyErr_SetString (PyExc_RuntimeError,            \
  64                          _("Block is invalid."));       \
  65         return NULL;                                    \
  66       }                                                 \
  67   } while (0)
  68
  69 /* Require a valid block.  This macro is called during block iterator
  70    creation, and at each next call.  */
  71 #define BLPY_ITER_REQUIRE_VALID(block_obj)                              \
  72   do {                                                                  \
  73     if (block_obj->block == NULL)                                       \
  74       {                                                                 \
  75         PyErr_SetString (PyExc_RuntimeError,                            \
  76                          _("Source block for iterator is invalid."));   \
  77         return NULL;                                                    \
  78       }                                                                 \
  79   } while (0)
  80
  81 extern PyTypeObject block_syms_iterator_object_type
  82     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("block_syms_iterator_object");
  83 static const struct objfile_data *blpy_objfile_data_key;
  84
  85 static PyObject *
  86 blpy_iter (PyObject *self)
  87 {
  88   block_syms_iterator_object *block_iter_obj;
  89   const struct block *block = NULL;
  90
  91   BLPY_REQUIRE_VALID (self, block);
  92
  93   block_iter_obj = PyObject_New (block_syms_iterator_object,
  94                                  &block_syms_iterator_object_type);
  95   if (block_iter_obj == NULL)
  96       return NULL;
  97
  98   block_iter_obj->block = block;
  99   block_iter_obj->initialized_p = 0;
 100   Py_INCREF (self);
 101   block_iter_obj->source = (block_object *) self;
 102
 103   return (PyObject *) block_iter_obj;
 104 }
 105
 106 static PyObject *
 107 blpy_get_start (PyObject *self, void *closure)
 108 {
 109   const struct block *block = NULL;
 110
 111   BLPY_REQUIRE_VALID (self, block);
 112
 113   return gdb_py_object_from_ulongest (BLOCK_START (block));
 114 }
 115
 116 static PyObject *
 117 blpy_get_end (PyObject *self, void *closure)
 118 {
 119   const struct block *block = NULL;
 120
 121   BLPY_REQUIRE_VALID (self, block);
 122
 123   return gdb_py_object_from_ulongest (BLOCK_END (block));
 124 }
 125
 126 static PyObject *
 127 blpy_get_function (PyObject *self, void *closure)
 128 {
 129   struct symbol *sym;
 130   const struct block *block;
 131
 132   BLPY_REQUIRE_VALID (self, block);
 133
 134   sym = BLOCK_FUNCTION (block);
 135   if (sym)
 136     return symbol_to_symbol_object (sym);
 137
 138   Py_RETURN_NONE;
 139 }
 140
 141 static PyObject *
 142 blpy_get_superblock (PyObject *self, void *closure)
 143 {
 144   const struct block *block;
 145   const struct block *super_block;
 146   block_object *self_obj  = (block_object *) self;
 147
 148   BLPY_REQUIRE_VALID (self, block);
 149
 150   super_block = BLOCK_SUPERBLOCK (block);
 151   if (super_block)
 152     return block_to_block_object (super_block, self_obj->objfile);
 153
 154   Py_RETURN_NONE;
 155 }
 156
 157 /* Return the global block associated to this block.  */
 158
 159 static PyObject *
 160 blpy_get_global_block (PyObject *self, void *closure)
 161 {
 162   const struct block *block;
 163   const struct block *global_block;
 164   block_object *self_obj  = (block_object *) self;
 165
 166   BLPY_REQUIRE_VALID (self, block);
 167
 168   global_block = block_global_block (block);
 169
 170   return block_to_block_object (global_block,
 171                                 self_obj->objfile);
 172
 173 }
 174
 175 /* Return the static block associated to this block.  Return None
 176    if we cannot get the static block (this is the global block).  */
 177
 178 static PyObject *
 179 blpy_get_static_block (PyObject *self, void *closure)
 180 {
 181   const struct block *block;
 182   const struct block *static_block;
 183   block_object *self_obj  = (block_object *) self;
 184
 185   BLPY_REQUIRE_VALID (self, block);
 186
 187   if (BLOCK_SUPERBLOCK (block) == NULL)
 188     Py_RETURN_NONE;
 189
 190   static_block = block_static_block (block);
 191
 192   return block_to_block_object (static_block, self_obj->objfile);
 193 }
 194
 195 /* Implementation of gdb.Block.is_global (self) -> Boolean.
 196    Returns True if this block object is a global block.  */
 197
 198 static PyObject *
 199 blpy_is_global (PyObject *self, void *closure)
 200 {
 201   const struct block *block;
 202
 203   BLPY_REQUIRE_VALID (self, block);
 204
 205   if (BLOCK_SUPERBLOCK (block))
 206     Py_RETURN_FALSE;
 207
 208   Py_RETURN_TRUE;
 209 }
 210
 211 /* Implementation of gdb.Block.is_static (self) -> Boolean.
 212    Returns True if this block object is a static block.  */
 213
 214 static PyObject *
 215 blpy_is_static (PyObject *self, void *closure)
 216 {
 217   const struct block *block;
 218
 219   BLPY_REQUIRE_VALID (self, block);
 220
 221   if (BLOCK_SUPERBLOCK (block) != NULL
 222      && BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) == NULL)
 223     Py_RETURN_TRUE;
 224
 225   Py_RETURN_FALSE;
 226 }
 227
 228 static void
 229 blpy_dealloc (PyObject *obj)
 230 {
 231   block_object *block = (block_object *) obj;
 232
 233   if (block->prev)
 234     block->prev->next = block->next;
 235   else if (block->objfile)
 236     {
 237       set_objfile_data (block->objfile, blpy_objfile_data_key,
 238                         block->next);
 239     }
 240   if (block->next)
 241     block->next->prev = block->prev;
 242   block->block = NULL;
 243 }
 244
 245 /* Given a block, and a block_object that has previously been
 246    allocated and initialized, populate the block_object with the
 247    struct block data.  Also, register the block_object life-cycle
 248    with the life-cycle of the object file associated with this
 249    block, if needed.  */
 250 static void
 251 set_block (block_object *obj, const struct block *block,
 252            struct objfile *objfile)
 253 {
 254   obj->block = block;
 255   obj->prev = NULL;
 256   if (objfile)
 257     {
 258       obj->objfile = objfile;
 259       obj->next = objfile_data (objfile, blpy_objfile_data_key);
 260       if (obj->next)
 261         obj->next->prev = obj;
 262       set_objfile_data (objfile, blpy_objfile_data_key, obj);
 263     }
 264   else
 265     obj->next = NULL;
 266 }
 267
 268 /* Create a new block object (gdb.Block) that encapsulates the struct
 269    block object from GDB.  */
 270 PyObject *
 271 block_to_block_object (const struct block *block, struct objfile *objfile)
 272 {
 273   block_object *block_obj;
 274
 275   block_obj = PyObject_New (block_object, &block_object_type);
 276   if (block_obj)
 277     set_block (block_obj, block, objfile);
 278
 279   return (PyObject *) block_obj;
 280 }
 281
 282 /* Return struct block reference that is wrapped by this object.  */
 283 const struct block *
 284 block_object_to_block (PyObject *obj)
 285 {
 286   if (! PyObject_TypeCheck (obj, &block_object_type))
 287     return NULL;
 288   return ((block_object *) obj)->block;
 289 }
 290
 291 /* Return a reference to the block iterator.  */
 292 static PyObject *
 293 blpy_block_syms_iter (PyObject *self)
 294 {
 295   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
 296
 297   BLPY_ITER_REQUIRE_VALID (iter_obj->source);
 298
 299   Py_INCREF (self);
 300   return self;
 301 }
 302
 303 /* Return the next symbol in the iteration through the block's
 304    dictionary.  */
 305 static PyObject *
 306 blpy_block_syms_iternext (PyObject *self)
 307 {
 308   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
 309   struct symbol *sym;
 310
 311   BLPY_ITER_REQUIRE_VALID (iter_obj->source);
 312
 313   if (!iter_obj->initialized_p)
 314     {
 315       sym = block_iterator_first (iter_obj->block,  &(iter_obj->iter));
 316       iter_obj->initialized_p = 1;
 317     }
 318   else
 319     sym = block_iterator_next (&(iter_obj->iter));
 320
 321   if (sym == NULL)
 322     {
 323       PyErr_SetString (PyExc_StopIteration, _("Symbol is null."));
 324       return NULL;
 325     }
 326
 327   return symbol_to_symbol_object (sym);
 328 }
 329
 330 static void
 331 blpy_block_syms_dealloc (PyObject *obj)
 332 {
 333   block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) obj;
 334
 335   Py_XDECREF (iter_obj->source);
 336 }
 337
 338 /* Implementation of gdb.Block.is_valid (self) -> Boolean.
 339    Returns True if this block object still exists in GDB.  */
 340
 341 static PyObject *
 342 blpy_is_valid (PyObject *self, PyObject *args)
 343 {
 344   const struct block *block;
 345
 346   block = block_object_to_block (self);
 347   if (block == NULL)
 348     Py_RETURN_FALSE;
 349
 350   Py_RETURN_TRUE;
 351 }
 352
 353 /* Implementation of gdb.BlockIterator.is_valid (self) -> Boolean.
 354    Returns True if this block iterator object still exists in GDB  */
 355
 356 static PyObject *
 357 blpy_iter_is_valid (PyObject *self, PyObject *args)
 358 {
 359   block_syms_iterator_object *iter_obj =
 360     (block_syms_iterator_object *) self;
 361
 362   if (iter_obj->source->block == NULL)
 363     Py_RETURN_FALSE;
 364
 365   Py_RETURN_TRUE;
 366 }
 367
 368 /* Return the innermost lexical block containing the specified pc value,
 369    or 0 if there is none.  */
 370 PyObject *
 371 gdbpy_block_for_pc (PyObject *self, PyObject *args)
 372 {
 373   gdb_py_ulongest pc;
 374   const struct block *block = NULL;
 375   struct compunit_symtab *cust = NULL;
 376
 377   if (!PyArg_ParseTuple (args, GDB_PY_LLU_ARG, &pc))
 378     return NULL;
 379
 380   TRY
 381     {
 382       cust = find_pc_compunit_symtab (pc);
 383
 384       if (cust != NULL && COMPUNIT_OBJFILE (cust) != NULL)
 385         block = block_for_pc (pc);
 386     }
 387   CATCH (except, RETURN_MASK_ALL)
 388     {
 389       GDB_PY_HANDLE_EXCEPTION (except);
 390     }
 391   END_CATCH
 392
 393   if (cust == NULL || COMPUNIT_OBJFILE (cust) == NULL)
 394     {
 395       PyErr_SetString (PyExc_RuntimeError,
 396                        _("Cannot locate object file for block."));
 397       return NULL;
 398     }
 399
 400   if (block)
 401     return block_to_block_object (block, COMPUNIT_OBJFILE (cust));
 402
 403   Py_RETURN_NONE;
 404 }
 405
 406 /* This function is called when an objfile is about to be freed.
 407    Invalidate the block as further actions on the block would result
 408    in bad data.  All access to obj->symbol should be gated by
 409    BLPY_REQUIRE_VALID which will raise an exception on invalid
 410    blocks.  */
 411 static void
 412 del_objfile_blocks (struct objfile *objfile, void *datum)
 413 {
 414   block_object *obj = datum;
 415
 416   while (obj)
 417     {
 418       block_object *next = obj->next;
 419
 420       obj->block = NULL;
 421       obj->objfile = NULL;
 422       obj->next = NULL;
 423       obj->prev = NULL;
 424
 425       obj = next;
 426     }
 427 }
 428
 429 int
 430 gdbpy_initialize_blocks (void)
 431 {
 432   block_object_type.tp_new = PyType_GenericNew;
 433   if (PyType_Ready (&block_object_type) < 0)
 434     return -1;
 435
 436   block_syms_iterator_object_type.tp_new = PyType_GenericNew;
 437   if (PyType_Ready (&block_syms_iterator_object_type) < 0)
 438     return -1;
 439
 440   /* Register an objfile "free" callback so we can properly
 441      invalidate blocks when an object file is about to be
 442      deleted.  */
 443   blpy_objfile_data_key
 444     = register_objfile_data_with_cleanup (NULL, del_objfile_blocks);
 445
 446   if (gdb_pymodule_addobject (gdb_module, "Block",
 447                               (PyObject *) &block_object_type) < 0)
 448     return -1;
 449
 450   return gdb_pymodule_addobject (gdb_module, "BlockIterator",
 451                                  (PyObject *) &block_syms_iterator_object_type);
 452 }
 453
 454 \f
 455
 456 static PyMethodDef block_object_methods[] = {
 457   { "is_valid", blpy_is_valid, METH_NOARGS,
 458     "is_valid () -> Boolean.\n\
 459 Return true if this block is valid, false if not." },
 460   {NULL}  /* Sentinel */
 461 };
 462
 463 static PyGetSetDef block_object_getset[] = {
 464   { "start", blpy_get_start, NULL, "Start address of the block.", NULL },
 465   { "end", blpy_get_end, NULL, "End address of the block.", NULL },
 466   { "function", blpy_get_function, NULL,
 467     "Symbol that names the block, or None.", NULL },
 468   { "superblock", blpy_get_superblock, NULL,
 469     "Block containing the block, or None.", NULL },
 470   { "global_block", blpy_get_global_block, NULL,
 471     "Block containing the global block.", NULL },
 472   { "static_block", blpy_get_static_block, NULL,
 473     "Block containing the static block.", NULL },
 474   { "is_static", blpy_is_static, NULL,
 475     "Whether this block is a static block.", NULL },
 476   { "is_global", blpy_is_global, NULL,
 477     "Whether this block is a global block.", NULL },
 478   { NULL }  /* Sentinel */
 479 };
 480
 481 PyTypeObject block_object_type = {
 482   PyVarObject_HEAD_INIT (NULL, 0)
 483   "gdb.Block",                    /*tp_name*/
 484   sizeof (block_object),          /*tp_basicsize*/
 485   0,                              /*tp_itemsize*/
 486   blpy_dealloc,                   /*tp_dealloc*/
 487   0,                              /*tp_print*/
 488   0,                              /*tp_getattr*/
 489   0,                              /*tp_setattr*/
 490   0,                              /*tp_compare*/
 491   0,                              /*tp_repr*/
 492   0,                              /*tp_as_number*/
 493   0,                              /*tp_as_sequence*/
 494   0,                              /*tp_as_mapping*/
 495   0,                              /*tp_hash */
 496   0,                              /*tp_call*/
 497   0,                              /*tp_str*/
 498   0,                              /*tp_getattro*/
 499   0,                              /*tp_setattro*/
 500   0,                              /*tp_as_buffer*/
 501   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
 502   "GDB block object",             /* tp_doc */
 503   0,                              /* tp_traverse */
 504   0,                              /* tp_clear */
 505   0,                              /* tp_richcompare */
 506   0,                              /* tp_weaklistoffset */
 507   blpy_iter,                      /* tp_iter */
 508   0,                              /* tp_iternext */
 509   block_object_methods,           /* tp_methods */
 510   0,                              /* tp_members */
 511   block_object_getset             /* tp_getset */
 512 };
 513
 514 static PyMethodDef block_iterator_object_methods[] = {
 515   { "is_valid", blpy_iter_is_valid, METH_NOARGS,
 516     "is_valid () -> Boolean.\n\
 517 Return true if this block iterator is valid, false if not." },
 518   {NULL}  /* Sentinel */
 519 };
 520
 521 PyTypeObject block_syms_iterator_object_type = {
 522   PyVarObject_HEAD_INIT (NULL, 0)
 523   "gdb.BlockIterator",            /*tp_name*/
 524   sizeof (block_syms_iterator_object),        /*tp_basicsize*/
 525   0,                              /*tp_itemsize*/
 526   blpy_block_syms_dealloc,        /*tp_dealloc*/
 527   0,                              /*tp_print*/
 528   0,                              /*tp_getattr*/
 529   0,                              /*tp_setattr*/
 530   0,                              /*tp_compare*/
 531   0,                              /*tp_repr*/
 532   0,                              /*tp_as_number*/
 533   0,                              /*tp_as_sequence*/
 534   0,                              /*tp_as_mapping*/
 535   0,                              /*tp_hash */
 536   0,                              /*tp_call*/
 537   0,                              /*tp_str*/
 538   0,                              /*tp_getattro*/
 539   0,                              /*tp_setattro*/
 540   0,                              /*tp_as_buffer*/
 541   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
 542   "GDB block syms iterator object",           /*tp_doc */
 543   0,                              /*tp_traverse */
 544   0,                              /*tp_clear */
 545   0,                              /*tp_richcompare */
 546   0,                              /*tp_weaklistoffset */
 547   blpy_block_syms_iter,           /*tp_iter */
 548   blpy_block_syms_iternext,       /*tp_iternext */
 549   block_iterator_object_methods   /*tp_methods */
 550 };